In recent years, in the field of a display unit that performs an image display, a display unit has been developed that uses, as a light-emitting device in a pixel, a current-driven type optical device in which the emission luminance varies depending on a value of a flowing current, such as an organic EL device, and the product commercialization of such a display unit has been carried forward. Unlike a liquid crystal device and the like, the organic EL device is a self-emitting device. Therefore, a display unit using the organic EL device (an organic EL display unit) eliminates the necessity for the use of a light source (backlight), and thus it is possible to achieve the lower-profile appearance and the higher luminance as compared with a liquid crystal display unit involving a light source. Especially, when an active-matrix method is used as a drive method, it is possible to make each pixel luminous in a hold state, as well as to reduce the power consumption. Accordingly, it is expected that the organic EL display unit will go mainstream of a next-generation flat-panel display.
In an active-matrix display unit, a current flowing through an organic EL device that is arranged on each pixel basis is controlled by a thin-film transistor (TFT) that is provided within a pixel circuit provided for each of the organic EL devices (for example, see PTL 1).